43,291 research outputs found
Endocrine adaptations across physical and psychological stressors in long-term space flights
No full textThe human body needs to adapt to both psychological pressure and physical stressors, such as radiation and microgravity, to cope with the extreme environment represented by a long-term spaceflight. Resolving the relative contributions of physical and psychological stressors and the mechanisms underlying adaptation remains critical for devising effective countermeasures addressing the health and well-being of humans heading to prospective deep-space exploratory-class missions. In the present short review, we discuss recent evidence on the complex role of novel players linking the response to physical and psychological stressors with health-impacting consequences of long-term space flights, such as bone loss and dysregulated immune response
Monoacylglycerol lipase (MAGL) inhibitors based on a diphenylsulfide-benzoylpiperidine scaffold
No full textMonoacylglycerol lipase (MAGL) is an enzyme belonging to the endocannabinoid system that mainly metabolizes the endocannabinoid 2-arachidonoylglycerol (2-AG). Numerous studies have shown the involvement of this enzyme in various pathological conditions such as pain, cancer progression, Parkinson's and Alzheimer's disease, thus encouraging the development of new MAGL modulators. In this context, we developed new diphenylsulfide-benzoylpiperidine derivatives characterized by a high enzymatic MAGL inhibition activity in the low nanomolar range, a reversible mechanism of action and selectivity. The three most active compounds (15–17) induced an appreciable inhibition of cell viability in a panel of nine cancer cell lines, with IC50 values ranging between 0.32 and 10 μM, thus highlighting their potential as novel anticancer agents
Can the Head-Shaking Test be attributed real clinical value in otoneurological diagnostics?
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Linguaggi e pratiche del potere. Genova e il regno di Napoli tra Medioevo ed Età moderna, a c. di G. Petti Balbi, G. Vitolo, Salerno, 2007- 421 p.
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Reverse Mössbauer Effect as a Source of “Hot” Protons in Hydrogen Absorbing Metals
No full textAs an attempt to explain some of the many anomalies and unresolved problems, which have been reported about the dynamic behavior of particles and molecules absorbed in crystalline solids, in a recent paper (1) we derived an extension of the Bragg – von Laue scattering law to high-energy colliding particles, which is related also to the Mössbauer effect (2), and was referred to as “reverse Mössbauer effect” (RME). In particular, we proposed an explanation of a specific and well characterized anomalous behavior found in neutron inelastic-scattering spectra (recoiled bands) of methane adsorbed in a zeolite (3).
According to RME, a particle in non-equilibrium state with respect to a crystal (colliding with the crystal or adsorbed/absorbed in it, and, set out of thermal equilibrium with the crystal by some external cause), can be scattered by the whole crystal with momentum proportional to a vector representing a reciprocal lattice point. The scattering is expected to occur with a well-defined probability and the momentum transferable to the particle is expected to follow a predictable distribution.
As hydrogen is lighter than methane and is adsorbed not only in nanoporous materials, but also is absorbed in a number of metals, we wondered if RME could be present also in H-metal systems and could be detected through some anomalous behavior. RME is essentially a non-equilibrium phenomenon occurring in crystals. Therefore, it could be detected, in principle, by looking for behaviors, which for similar systems differ whether the systems are or not in equilibrium, as well as whether they are crystalline or amorphous.
Enhanced diffusion of H under irradiation by ions and electrons (4,5) was observed. Enhanced diffusion was even reported for hydrogen atoms absorbed in bulk Pd in low-temperature scanning tunneling microscopy (6). In a recent paper (7), the interpretation of the anisotropic diffusion of hydrogen in Nickel required unexpectedly high fitting parameters, at least one order of magnitude larger than the values derived from experimental and ab initio studies.
The consideration of all these phenomena encouraged us to study the features of the RME for H absorbed in metals, and, as some examples, we evaluated its general features for H absorbed in Ni, Nb, Pd and Ti, because they are among the most frequently studied systems.
It was then applied to explain, at least in part, the above reported anomalies.
References: 1. P. Demontis, G. B. Suffritti, J. Chem. Phys. 145, 094110 (2016). 2. R. L. Mössbauer, Zeit. Phys. 151, 124 (1958). 3. H. Jobic, Chem. Phys. Lett. 170, 217 (1990). 4. P. Chemov , A.P. Mamontov, Y.I. Tjurin, Y.P. Cherdantsev, J. Nucl. Mater. 233-237, 1118 (1996). 5. I. Chernov, Yu. Tyurin, Yu. P. Cherdantzev, M. Kröning, H. Baumbach, Int. J. Hydrogen Energy 24, 359 (1999) 6. E. C. H. Sykes, L. C. Fernández-Torres, S. U. Nanayakkara, B. A. Mantooth, R. M. Nevin, P. S. Weiss, Proc. Natl. Acad. Sci. U.S.A. 102, 17907 (2005). 7. J. Li, A. Oudriss, A. Metsue, J. Bouhattate, X. Feaugas, Sci. Rep. 7, 45041 (2017)
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